Reaction #1833218

Reaction equation

2,2,5-trifluorobenzo[d][1,3]dioxole

Sec-Butyllithium

iodine

→

title compound

Yield 58.4%

2,2,5-Trifluoro-4-iodobenzo[d][1,3]dioxole

Yield 58.4%

Solvents

tetrahydrofuran

tetrahydrofuran

Conditions

Workup

1. 1
   TemperatureThe solution was cooled to −75° C.
2. 2
   Temperaturethe mixture was cooled to −75° C
3. 3
   workup.STIRRINGThe mixture was stirred for 1 h during which time the temperature
4. 4
   Otherrose to −20° C
5. 5
   OtherThe reaction was quenched by addition of saturated NH4Cl (10 mL)
6. 6
   WashThe organic phase was washed with saturated NaCl (10 mL)
7. 7
   Dryingdried (Na2SO4)
8. 8
   Otherevaporated
9. 9
   OtherThe material was purified by flash chromatography with hexane

Procedure

Sec-Butyllithium (1.4 M in cyclohexane; 6.1 mL, 8.5 mmol) was added to dry tetrahydrofuran (15 mL) which had been pre-cooled to −40° C. The solution was cooled to −75° C., treated with 2,2,5-trifluorobenzo[d][1,3]dioxole (1.5 g, 8.5 mmol) and stirred at this temperature for 90 min. This solution was rapidly transferred via cannula into a stirred solution of iodine (2.8 g, 11 mmol) in tetrahydrofuran (25 mL), and the mixture was cooled to −75° C. The mixture was stirred for 1 h during which time the temperature rose to −20° C. The reaction was quenched by addition of saturated NH4Cl (10 mL) and then combined with 10% NaHSO3 (15 mL) and ethyl acetate (30 mL). The organic phase was washed with saturated NaCl (10 mL), dried (Na2SO4) and evaporated. The material was purified by flash chromatography with hexane to give the title compound as a clear liquid (1.5 g, 58%): 1H NMR (400 MHz, CDCl3) δ 6.97 (dd, J=8.8, 4.0 Hz, 1H), 6.81 (dd, J=11.7, 5.4 Hz, 1H); 19F NMR (376 MHz, CDCl3) δ −49.06, −103.15; EIMS m/z 302.

Source